DCT

2:18-cv-06404

LG Innotek Co Ltd v. Melodysusie Brand Industrial Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:18-cv-06404, C.D. Cal., 07/25/2018
  • Venue Allegations: Venue is alleged to be proper because the foreign defendants are subject to personal jurisdiction within the district, and a substantial part of the events giving rise to the claims, including importation and sales of accused products, occurred in the Central District of California.
  • Core Dispute: Plaintiff alleges that Defendants’ MelodySusie brand UV/LED nail lamps incorporate light-emitting diode (LED) chips that infringe seven U.S. patents related to the structure, fabrication methods, and brightness-enhancing features of LEDs.
  • Technical Context: The dispute centers on the semiconductor device technology within light-emitting diodes, specifically Gallium-Nitride (GaN) based LEDs used for consumer applications such as curing nail gels.
  • Key Procedural History: The complaint alleges that Plaintiff provided Defendants with pre-suit notice of all asserted patents and the alleged infringement via a letter dated January 23, 2018. This correspondence may be central to the allegations of willful infringement.

Case Timeline

Date Event
2001-07-17 Earliest Priority Date for ’912 and ’713 Patents
2001-10-22 Earliest Priority Date for ’908 and ’585 Patents
2002-04-09 Earliest Priority Date for ’865 and ’360 Patents
2009-08-04 ’865 Patent Issued
2009-09-01 ’912 Patent Issued
2010-02-18 Earliest Priority Date for ’248 Patent
2010-08-31 ’908 Patent Issued
2012-08-07 ’585 Patent Issued
2013-08-06 ’248 Patent Issued
2015-12-08 ’360 Patent Issued
2017-05-02 ’713 Patent Issued
2018-01-23 Plaintiff sends pre-suit notice letter to Defendant affiliate
2018-02-23 Defendant affiliate acknowledges receipt of notice letter
2018-03-26 Plaintiff sends follow-up correspondence
2018-07-25 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,569,865 - "Method of Fabricating Vertical Structure LEDs"

The Invention Explained

  • Problem Addressed: The patent describes challenges in manufacturing Gallium-Nitride (GaN) based LEDs on insulating substrates like sapphire. Conventional "lateral" device structures, where both electrical contacts are on the top surface, limit the available area for light emission and are susceptible to electrostatic discharge (ESD) damage. Furthermore, dicing the hard sapphire substrate to separate individual LED chips is difficult, time-consuming, and reduces manufacturing yields (’865 Patent, col. 1:40 - col. 3:8).
  • The Patented Solution: The invention discloses a process for creating LEDs with a "vertical topology." This is achieved by first fabricating the semiconductor layers on the insulating substrate, bonding a new conductive metal support structure to the top, and then removing the original insulating substrate using a technique like laser lift-off. This results in a device where electrical current can flow vertically between a top contact and the bottom conductive support, which increases the light-emitting surface area and improves thermal dissipation (’865 Patent, Abstract; col. 4:1-11).
  • Technical Importance: This vertical architecture was designed to overcome the performance and manufacturing limitations inherent to building LEDs on insulating substrates, aiming for devices with higher efficiency, greater power handling, and improved manufacturing yields (’865 Patent, col. 4:1-11).

Key Claims at a Glance

  • The complaint asserts infringement of claim 1 (Compl. ¶47).
  • The essential elements of independent claim 1 include:
    • A conductive support structure.
    • A first-type GaN based layer over the support structure.
    • A first electrode located between the support structure and the first-type GaN layer.
    • A second-type GaN based layer over the first-type GaN layer.
    • A light-emitting layer between the first- and second-type GaN layers.
    • A passivation layer over the surfaces of the GaN and light-emitting layers and the first electrode.
    • A second electrode over the second-type GaN based layer.
    • The first and second electrodes are located on opposite sides of the light-emitting layer.
    • The passivation layer is located over at least an upper portion of the conductive support structure.
  • The complaint alleges infringement of "one or more claims" of the patent, reserving the right to assert additional claims (Compl. ¶41).

U.S. Patent No. 7,582,912 - "Diode Having High Brightness and Method Thereof"

The Invention Explained

  • Problem Addressed: In a standard LED, photons emitted downward toward the substrate can be absorbed by the substrate material or the device packaging. This absorption reduces the device's overall light extraction efficiency, resulting in lower brightness (’912 Patent, col. 2:5-10).
  • The Patented Solution: The invention proposes two features to increase brightness. First, it adds a reflective layer to the back surface of the substrate to reflect downward-traveling photons back out of the device. Second, it teaches that reducing the surface roughness of this back surface (e.g., through polishing or etching) enhances reflectivity and further increases the amount of recovered light (’912 Patent, Abstract; col. 4:29-43).
  • Technical Importance: This technology addresses a fundamental source of inefficiency in LEDs by providing a method to recover and redirect light that would otherwise be lost, thereby increasing the total optical output and brightness of the device (’912 Patent, col. 4:48-52).

Key Claims at a Glance

  • The complaint asserts infringement of claim 1 (Compl. ¶59).
  • The essential elements of independent claim 1 include:
    • A substrate.
    • An n-type layer, an active layer, and a p-type layer formed sequentially on a first surface of the substrate.
    • A first electrode contacting the p-type layer and a second electrode contacting the n-type layer.
    • A reflective layer on a second surface of the substrate.
    • A surface roughness of at least one portion of the interface between the reflective layer and the second surface of the substrate is less than 15 nm.
  • The complaint alleges infringement of "one or more claims" of the patent, reserving the right to assert additional claims (Compl. ¶54).

U.S. Patent No. 7,785,908 - "Method of Making Diode Having Reflective Layer"

  • Technology Synopsis: The patent claims a method for manufacturing a light-emitting device. The process includes forming semiconductor layers on a substrate, reducing the surface roughness of the substrate's second side through methods like mechanical polishing or dry etching, and then forming a reflective layer on that smoothed surface to enhance light reflectivity (’908 Patent, claim 1).
  • Asserted Claims: Claim 1 is asserted as exemplary (Compl. ¶71).
  • Accused Features: The complaint alleges that the process used to manufacture the Epileds model EP-U4545K-A3 LED chip, allegedly found in certain MelodySusie nail dryers, infringes the claimed method (Compl. ¶¶69-71).

U.S. Patent No. 8,236,585 - "Method of Making Diode Having Reflective Layer"

  • Technology Synopsis: The patent claims a method of making a "lateral type" light-emitting device. Key steps of the claimed process include forming semiconductor and electrode layers on a substrate, reducing the substrate's thickness to less than 350 µm, reducing the surface roughness of the substrate's back side, and forming a pad of a specific thickness on the electrodes (’585 Patent, claim 1).
  • Asserted Claims: Claim 1 is asserted as exemplary (Compl. ¶83).
  • Accused Features: The manufacturing process for the Epileds EP-U4545K-A3 LED chip is alleged to infringe the claimed method (Compl. ¶¶81-83).

U.S. Patent No. 8,502,248 - "Light Emitting Device, Having Protrusions From a Conductive Support Member, Lighting Emitting Device Package, and Lighting System"

  • Technology Synopsis: The patent claims a vertical light-emitting device where the conductive support member includes a "protrusion protruded from at least one edge." This protrusion is described as being "randomly protruded from an upper edge" and may contain a mixture of materials from both the electrode layer and the support member, suggesting it could be an artifact of the manufacturing process (’248 Patent, Abstract; claim 1).
  • Asserted Claims: Claim 1 is asserted as exemplary (Compl. ¶95).
  • Accused Features: The complaint accuses the Epileds model BN-U1515H-A3 vertical LED chip, allegedly used in certain MelodySusie products, of having the claimed protrusion structure (Compl. ¶¶93-95).

U.S. Patent No. 9,209,360 - "Vertical Topology Light-Emitting Device"

  • Technology Synopsis: The patent claims a vertical LED device with a detailed layer structure, including a support structure, an adhesion structure comprising gold (Au), first and second metal layers, and a GaN-based semiconductor structure. A key limitation relates to the dimensional relationship where the thickness of the support structure is 0.5 times or less than the side width of the GaN-based structure (’360 Patent, claim 15).
  • Asserted Claims: Claim 15 is asserted as exemplary (Compl. ¶107).
  • Accused Features: The Epileds BN-U1515H-A3 vertical LED chip is alleged to embody the claimed structure and dimensional relationships (Compl. ¶¶105, 107).

U.S. Patent No. 9,640,713 - "Diode Having High Brightness and Method Thereof"

  • Technology Synopsis: The patent claims a high-brightness LED device having a substrate thinned to less than 350 micrometers. The claimed structure includes specific semiconductor materials (e.g., an aluminum-gallium-nitride layer), electrodes with a multi-layer intermediate layer and a golden pad thicker than 500 nanometers, and a thin aluminum layer (less than 300 nanometers) on the back surface of the substrate (’713 Patent, claim 1).
  • Asserted Claims: Claim 1 is asserted as exemplary (Compl. ¶119).
  • Accused Features: The Epileds EP-U4545K-A3 lateral LED chip is alleged to infringe (Compl. ¶¶117-119).

III. The Accused Instrumentality

Product Identification

  • Various models of MelodySusie brand UV/LED Nail Dryers, including models designated "EOS," "Violetair," "Violetilac," and others (Compl. pp. 8-13).

Functionality and Market Context

  • The accused products are nail lamps that utilize LED chips to emit light, including ultraviolet light, for the purpose of curing nail gels (Compl. ¶¶6, 22, 26). The complaint identifies specific third-party LED chips, allegedly manufactured by Epileds, as the infringing components within the nail dryers (Compl. ¶¶23-30). A schematic from an Epileds product specification shows the layout of a lateral LED chip alleged to be in certain accused products (Compl. ¶23). The complaint alleges that Defendants' brand is one of the largest in the world for nail lamps, with substantial manufacturing volume and sales (Compl. ¶10).

IV. Analysis of Infringement Allegations

’865 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a conductive support structure A conductive support structure comprising at least titanium and/or silicon which is electrically conductive. ¶47a col. 9:6-7
a first-type GaN based layer over the conductive support structure A p-type GaN layer located in a layer over the conductive support structure. ¶47b col. 9:8-10
a first electrode disposed between the conductive support structure and the first-type GaN based layer such that the first-type GaN based layer is over the first electrode An electrode comprising gold or a gold alloy disposed between the conductive support structure and the p-type GaN layer. ¶47c col. 9:11-15
a second-type GaN based layer over the first-type GaN based layer An n-type GaN layer located in a layer over the p-type GaN layer. ¶47d col. 9:16-17
a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer A light-emitting layer located in a layer between the p-GaN layer and the n-GaN layer. ¶47e col. 9:18-20
a passivation layer over surfaces of the first-type GaN based layer, of the light emitting layer, of the second-type GaN based layer, and of the first electrode A passivation layer with silicon dioxide located in a layer over the surfaces of the p-type, light-emitting, and n-type semiconductor layers, and the first electrode. ¶47f col. 9:21-26
a second electrode over the second-type GaN based layer A second electrode comprising gold or a gold alloy in a layer located over the n-type GaN layer. ¶47g col. 9:27-28
wherein the first electrode and the second electrode are respectively located at opposite sides of the light-emitting layer... The first and second electrodes are respectively located on opposite sides of the light-emitting layer. ¶47h col. 9:29-32
...and wherein the passivation layer is located over at least an upper portion of the conductive support structure The passivation layer is located in a layer located over at least an upper portion of the conductive support structure. ¶47h col. 9:32-35
  • Identified Points of Contention:
    • Technical Questions: The complaint alleges the "conductive support structure" comprises "at least titanium and/or silicon" (Compl. ¶47a). However, the complaint's support for the accused vertical LED chip structure is a product specification that lists "gold (Au) backside metal" without mentioning titanium or silicon (Compl. ¶¶28, 44; Compl. p. 18). A schematic of the accused vertical LED chip is provided in the complaint (Compl. ¶28). The case may turn on evidence of the actual material composition of this support structure in the accused devices.
    • Scope Questions: What is the scope of a "conductive support structure"? A defendant may argue that this term, in the context of the patent, requires a material providing structural integrity beyond a simple metallic layer, raising the question of whether the "gold (Au) backside metal" meets this requirement.

’912 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a substrate An LED in the nail dryer has a substrate which provides surfaces. ¶59a col. 8:5
an n-type layer on a first surface of the substrate; an active layer on the n-type layer; a p-type layer on the active layer The LED has an n-type layer of Silicon doped GaN, an active layer of InGaN/GaN on the n-type layer, and a p-type layer comprising magnesium doped AlGaN and magnesium doped GaN on the active layer. ¶59b col. 8:6-8
a first electrode contacting the p-type layer An electrode contacting the p-type layer, comprising a chromium layer, a platinum layer, and a gold pad. ¶59c col. 8:9-10
a second electrode contacting the n-type layer Another electrode contacting the n-type layer, comprising a chromium layer, a platinum layer, and a gold pad. ¶59d col. 8:11-12
a reflective layer on a second surface of the substrate A reflective layer below the substrate, comprising aluminum and/or titanium dioxide and silicon dioxide layers which constitute a Distributed Bragg reflector. ¶59e col. 8:13-14
wherein a surface roughness of at least one portion of an interface between the reflective layer and the second surface of the substrate is less than 15 nm The interface has a surface roughness that measures approximately 10.01 nm, which is less than 15 nm. ¶59f col. 8:15-19
  • Identified Points of Contention:
    • Technical Questions: The central factual question will likely be the "surface roughness" limitation. The complaint makes a highly specific allegation that the roughness is "approximately 10.01 nm" but does not provide the source or methodology for this measurement (Compl. ¶59f). The ability to substantiate this precise physical characteristic will be critical.

V. Key Claim Terms for Construction

  • Patent: ’865 Patent

    • The Term: "conductive support structure"
    • Context and Importance: This term defines the foundation of the claimed vertical LED. The infringement allegation hinges on whether the "gold (Au) backside metal" identified in a third-party product specification (Compl. ¶28) for the accused LED falls within the scope of this term, particularly as the complaint also alleges the structure contains titanium or silicon (Compl. ¶47a).
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification provides a non-exhaustive list of suitable materials, stating the "metal support layer can be Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, or Al" ('865 Patent, col. 8:49-51). This explicit inclusion of "Au" (gold) may support an interpretation where a gold layer alone can serve as the claimed structure.
      • Evidence for a Narrower Interpretation: The patent repeatedly refers to the element as a "structure" and a "layer" that provides "structural stability" and is formed to a significant thickness (e.g., "approximately 50 µm") ('865 Patent, col. 4:1-2; col. 8:40-41). A defendant might argue that the term implies more than just a conductive coating and requires a component that provides mechanical support akin to the original substrate it replaces.

  • Patent: ’912 Patent

    • The Term: "surface roughness... is less than 15 nm"
    • Context and Importance: This is a dispositive numerical limitation. Infringement requires proof that the accused devices meet this specific, quantitative threshold. The dispute will likely focus on the measurement methodology and whether the products' actual surface roughness falls below 15 nm.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim provides a clear numerical ceiling ("less than 15 nm"), which is not ambiguous on its face. The focus of construction would likely be on establishing a standard methodology for measurement, which the patent does not specify.
      • Evidence for a Narrower Interpretation: The specification describes achieving an "atomically flat sapphire surface" with roughness "as small as 1 nm" using techniques like ICPRIE ('912 Patent, col. 4:45-48). While the claim sets a 15 nm limit, this description of achieving a much smoother surface provides context for the invention's objective, which a party could argue informs the meaning and proper measurement of the claimed term.

VI. Other Allegations

  • Indirect Infringement: For all asserted patents, the complaint alleges both induced and contributory infringement. It alleges inducement is based on Defendants encouraging customers to use the infringing nail dryers for their intended purpose. Contributory infringement is alleged on the basis that the accused LED chips are a material part of the invention, are not staple articles of commerce, and have no substantial non-infringing use, as they are "essential to the nail gel curing process" (e.g., Compl. ¶¶42-43).
  • Willful Infringement: Willfulness is alleged for all asserted patents. The primary basis for this allegation is pre-suit knowledge stemming from a detailed notice letter Plaintiff sent on January 23, 2018, which allegedly identified all patents-in-suit, the accused products, and the infringement (Compl. ¶¶31-32, 48). The complaint further notes that Defendants' affiliate acknowledged receipt of this letter but did not cease the allegedly infringing activity (Compl. ¶33).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of evidentiary proof: The complaint relies heavily on third-party product specifications to allege the internal structure of the accused LED chips. A key question for the case will be whether discovery confirms the highly specific factual allegations regarding material compositions (e.g., the presence of titanium/silicon) and physical properties (e.g., a surface roughness below 15 nm) required by the asserted claims.
  • Another core issue will be one of process imputation: Several patents claim methods of manufacturing LEDs. Given that the accused chips are allegedly made by a third party (Epileds), a critical question will be what evidence the plaintiff can adduce to prove, by a preponderance of the evidence, that these specific chips were in fact made using the patented manufacturing steps.
  • Finally, the case may turn on a question of definitional scope, particularly for the '248 patent: can a feature that may be a manufacturing artifact, such as the alleged "protrusion," be construed to meet the specific claim limitations of being "randomly protruded" and comprising a "mixture of materials," or does the claim require a more deliberately formed structure?